Conventional ink jet printers include a printhead and a carrier. The ink jet printhead may comprise a printhead body, nozzles, and corresponding ink ejection actuators. The actuators cause ink to be ejected from the nozzles onto a print medium at selected ink dot locations within an image area. The carrier moves the printhead relative to the medium, while the ink dots are jetted onto selected pixel locations.
A common type of inkjet printer uses a replaceable print cartridge which may contain a printhead and a supply of ink contained within the print cartridge. The print cartridge is not intended to be refillable and when the initial supply of ink is depleted, the print cartridge is discarded and a new print cartridge is installed within the scanning carriage. The tanks on these types of print cartridges will typically have small liquid volumes, as low as 10 mL in some cases, which may require frequent replacement.
More expensive, business grade printers use progressively larger ink tanks on the printhead, but as the print swath width and/or height, and/or the speed at which the printhead moves increases, it eventually becomes impractical to have the tanks integrated with the printheads due to the high mass and inertia the liquid volume adds to the printheads, which results in reduced printing accuracy. Further, with ink tanks located on the printhead, replacement typically requires repriming and alignment checks that necessarily require aborting any current job.
To overcome this problem, it is known to provide a stationary, external fluid supply connected to the print cartridge. Examples are described in U.S. Pat. Nos. 5,980,032, 5,751,319, 8,371,682, and 6,843,558, to name a few. Ink flows from the external fluid supply into the print cartridge through a fluidic connection, as needed. External fluid delivery systems can be refilled or reprimed without disrupting a very large or expensive printing task.
However, external fluid delivery systems have several drawbacks. Existing external fluid delivery systems are not customizable; printhead assemblies in these systems are typically sold with ink and are designed to be used only for that system. Thus, existing systems lack versatility for multiple purpose use. Other drawbacks of existing external fluid delivery systems include: undesirable fluctuations in ink pressure in the print cartridge, an unreliable and complex fluid seal between the print cartridge and the external ink supply, a difficult fluid connection alignment process from the print cartridge to the external ink supply, increased printer size due to the external ink supply's connection to the print cartridge, blockage in the ink delivery system, air accumulation in the tubes leading to the print cartridge, leakage of ink, high cost, and complexity.
A further disadvantage is that current external fluid delivery systems, specifically printhead assemblies, require complex assembly and manufacturing processes. These parts may have a large footprint on the assembly line, which typically requires additional tooling and cost to complete the manufacturing process.